Liquid crystal display device

ABSTRACT

A liquid crystal display device including a first substrate including a first display electrode and a second display electrode that is disposed opposite the first display electrode with an insulator interposed between the first display electrode and the second display electrode, a second substrate disposed opposite the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate. In each pixel, the first display electrode includes a plurality of first openings, and the second display electrode includes a plurality of second openings disposed corresponding to positions of the plurality of first openings.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a bypass continuation of international patentapplication PCT/JP2016/001070, filed on Feb. 26, 2016 designating theUnited States of America. Priority is claimed based on a Japanese patentapplication JP2015-110546, filed on May 29, 2015. The entire disclosuresof these international and Japanese patent applications are incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a liquid crystal display device,especially a lateral electric field system liquid crystal displaydevice.

BACKGROUND

In various liquid crystal display devices, a lateral electric fieldsystem liquid crystal display device (for example, see JapaneseUnexamined Patent Application Publication No. 2008-180928) has anadvantage of an excellent wide viewing angle characteristic. Forexample, the lateral electric field system liquid crystal display deviceincludes a pixel electrode and a common electrode in one of a pair ofsubstrates, which are disposed opposite each other with a liquid crystallayer interposed between the pair of substrates. An electric field(lateral electric field) in a direction parallel to a substrate surfaceis generated between the pixel electrode and the common electrode, andthe lateral electric field is applied to liquid crystal to drive theliquid crystal, whereby an amount of light transmitted through theliquid crystal layer is controlled to display an image. Examples of thelateral electric field system include an IPS (In Plane Switching) systemand an FFS (Fringe Field Switching) system.

However, in the conventional lateral electric field system liquidcrystal display device, a response speed of the liquid crystal isdelayed due to a large size of each domain formed in a pixel and a smallnumber of the domains.

The present disclosure has been made in view of the above problem, andan object thereof is to improve the viewing angle characteristic and theresponse speed in the lateral electric field system liquid crystaldisplay device.

SUMMARY

In one general aspect, the instant application describes a liquidcrystal display device including a first substrate including a firstdisplay electrode and a second display electrode that is disposedopposite the first display electrode with an insulator interposedbetween the first display electrode and the second display electrode, asecond substrate disposed opposite the first substrate, and a liquidcrystal layer disposed between the first substrate and the secondsubstrate. In each pixel, the first display electrode includes aplurality of first openings, and the second display electrode includes aplurality of second openings disposed corresponding to positions of theplurality of first openings.

The above general aspect may include one or more of the followingfeatures.

At least a part in each of the plurality of second openings may overlapwith an electrode portion between the two first openings adjacent toeach other in the first display electrode in planar view.

A whole opening region in each of the plurality of second openings mayoverlap with each of the plurality of first openings in planar view.

The plurality of second openings may be arranged in a directionorthogonal to a long direction of the first opening.

The plurality of second openings may be arranged in a long direction ofthe first opening.

In each of the plurality of second openings, a width in a firstdirection that is of a direction in which the plurality of firstopenings are arranged may be equal to a width in the first direction ofan electrode portion between the two first openings adjacent to eachother or a width in the first direction of the first opening.

Each of the plurality of first openings may be formed into a rectangularshape, and each of the plurality of second openings may be formed intoone of a square shape, a rectangular shape, a triangular shape, arhombic shape, a polygonal shape, a circular shape, and an ellipticshape.

One of the first display electrode and the second display electrode maybe disposed in a lower layer, and another one of the first displayelectrode and the second display electrode may be disposed in an upperlayer with the insulator interposed between the first display electrodeand the second display electrode.

At least one of the first substrate and the second substrate may includea projection that controls alignment of liquid crystal.

One of the first display electrode and the second display electrode maybe a pixel electrode, and another one of the first display electrode andthe second display electrode may be a common electrode.

The plurality of first openings may be disposed in parallel to eachother, and the plurality of first openings may be disposed such that along direction of the first opening is parallel to a short direction ofthe pixel.

In the liquid crystal display device of the present disclosure, alateral electric field system liquid crystal display device can achievea wide viewing angle characteristic and high-speed response time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a schematic configuration of a liquidcrystal display device according to an exemplary embodiment;

FIG. 2 is a plan view illustrating a configuration of pixel;

FIG. 3 is a sectional view taken along line A-A in FIG. 2;

FIG. 4 is a sectional view taken along line B-B in FIG. 2;

FIG. 5 is a sectional view taken along line C-C in FIG. 2;

FIGS. 6A, 6B and 6C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 1;

FIGS. 7A, 7B and 7C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 2;

FIGS. 8A, 8B and 8C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 3;

FIGS. 9A, 9B and 9C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 4;

FIGS. 10A, 10B and 10C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 5;

FIGS. 11A, 11B and 11C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 6;

FIGS. 12A, 12B and 12C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 7;

FIGS. 13A, 13B and 13C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 8;

FIGS. 14A, 14B and 14C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 9;

FIGS. 15A, 15B and 15C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 10;

FIGS. 16A, 16B and 16C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 11;

FIGS. 17A, 17B and 17C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 12;

FIGS. 18A, 18B and 18C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 13;

FIGS. 19A, 19B and 19C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 14;

FIGS. 20A, 20B and 20C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 15;

FIGS. 21A, 21B and 21C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 16;

FIGS. 22A, 22B and 22C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 17;

FIGS. 23A, 23B and 23C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 18;

FIGS. 24A, 24B and 24C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 19;

FIGS. 25A, 25B and 25C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 20;

FIGS. 26A, 26B and 26C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 21;

FIGS. 27A, 27B and 27C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 22;

FIGS. 28A, 28B and 28C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 23;

FIGS. 29A, 29B and 29C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 24;

FIGS. 30A, 30B and 30C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 25;

FIGS. 31A, 31B and 31C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 26;

FIGS. 32A, 32B and 32C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 27;

FIGS. 33A, 33B and 33C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 28;

FIGS. 34A, 34B and 34C are plan views schematically illustrating pixelelectrode and common electrode of configuration example 29;

FIGS. 35A, 35B, 35C and 35D are plan views schematically illustratingother configurations of a pixel electrode;

FIG. 36 is a cross section view illustrating another schematicconfiguration of a liquid crystal display device;

FIG. 37 is a cross section view illustrating another schematicconfiguration of a liquid crystal display device;

FIG. 38 is a cross section view illustrating another schematicconfiguration of a liquid crystal display device; and

FIG. 39 is a graph illustrating simulations of the responsecharacteristics.

DETAILED DESCRIPTION

An embodiment of the present application is described below withreference to the drawings.

FIG. 1 is a plan view illustrating a schematic configuration of a liquidcrystal display device according to an exemplary embodiment. Liquidcrystal display device 1 includes display panel 10 that displays animage, a driving circuit (a data line driving circuit and a gate linedriving circuit) that drives display panel 10, a control circuit (notillustrated) that controls the driving circuit, and a backlight (notillustrated) that irradiates display panel 10 with light from a rearsurface side. The driving circuit may be provided in display panel 10.

A plurality of data lines 11 extending in a column direction and aplurality of gate lines 12 extending in a row direction are provided indisplay panel 10. Thin film transistor (TFT) 13 is provided in anintersection of each data line 11 and each gate line 12.

In display panel 10, a plurality of pixels 14 are arranged into a matrixshape (the row direction and the column direction) corresponding to theintersections of data lines 11 and gate lines 12. Although beingdescribed in detail later, display panel 10 includes a thin filmtransistor substrate (TFT substrate), a color filter substrate (CFsubstrate), and a liquid crystal layer sandwiched between the TFTsubstrate and the CF substrate. A plurality of pixel electrodes 15disposed corresponding to each pixel 14 and one common electrode 16common to the plurality of pixels 14 are provided in TFT substrate.Common electrode 16 is disposed while divided in each one pixel 14 oreach plurality of pixels 14. Pixel electrode 15 and common electrode 16act as a display electrode.

FIG. 2 is a plan view illustrating a configuration of pixel 14. FIG. 3is a sectional view taken along line A-A in FIG. 2, FIG. 4 is asectional view taken along line B-B in FIG. 2, and FIG. 5 is a sectionalview taken along line C-C in FIG. 2. A specific configuration of displaypanel 10 will be described with reference to FIGS. 2 to 5.

In FIG. 2, a region partitioned by two adjacent data lines 11 and twoadjacent gate lines 12 corresponds to one pixel 14. Thin film transistor13 is provided in each pixel 14. Thin film transistor 13 includessemiconductor layer 21 formed on insulator 102 (see FIG. 3) and drainelectrode 22 and source electrode 23, which are formed on semiconductorlayer 21 (see FIG. 2). Drain electrode 22 is electrically connected todata line 11, and source electrode 23 is electrically connected to pixelelectrode 15 through through-hole 24.

Pixel electrode 15 made of a transparent conductive film such as indiumtin oxide (ITO) is formed in each pixel 14. Pixel electrode 15 includesa plurality of openings 15 a (slits), and is formed into a stripe shape.Each opening 15 a is formed into a horizontally-long rectangular shape,long sides of four sides constituting opening 15 a extend in a rowdirection, and short sides extend in a column direction. The pluralityof openings 15 a have a substantially identical shape, and are arrangedat substantially equal intervals in the column direction. Openings 15 aare formed so as to be symmetric with respect to a center in the rowdirection of pixel 14. There is no limitation to the number of openings15 a formed in one pixel electrode 15. A shape of opening 15 a is notlimited to the shape in FIG. 2. For example, opening 15 a may be formedsuch that an interior angle of at least one apex constituting opening 15a is different from interior angles of other apexes. In other words,opening 15 a may be formed such that at least one side constitutingopening 15 a extends in an oblique direction with respect to othersides. Openings 15 a may be disposed in parallel to each other, and along direction of opening 15 a may be disposed in parallel to a shortdirection of pixel 14. Openings 15 a may be disposed in parallel to eachother, and the long direction of opening 15 a may be disposed so as toextend in the oblique direction with respect to the short direction ofpixel 14.

One common electrode 16 made of a transparent conductive film such asITO is formed commonly in each pixel 14 over a display region. Commonelectrode 16 includes a plurality of openings 16 a corresponding to eachpixel 14. Each opening 16 a is formed into a square shape, two sidesopposite each other in four sides constituting opening 16 a extend inthe row direction, and other two sides opposite each other extend in thecolumn direction. The plurality of openings 16 a have a substantiallyidentical shape, and are arranged at substantially equal intervals inthe column direction. Openings 16 a are formed so as to be symmetricwith respect to the center in the row direction of pixel 14. Eachopening 16 a is disposed so as to overlap with a region (electrodeportion) between two openings 15 a adjacent to each other in the columndirection of the pixel electrode 15 in planar view. Therefore, forexample, opening 15 a of pixel electrode 15 and opening 16 a of commonelectrode 16 are alternately disposed in the column direction in planarview. There is no limitation to a shape, a number, and a position ofopening 16 a. Other configuration examples of opening 16 a will bedescribed later. An opening is formed in a region where common electrode16 overlaps with through-hole 24 and source electrode 23 of thin filmtransistor 13 in order to electrically connect pixel electrode 15 andsource electrode 23.

As illustrated in FIG. 3, display panel 10 includes TFT substrate 100(first substrate) disposed on the rear surface side, CF substrate 200(second substrate) disposed on the display surface side, and liquidcrystal layer 300 sandwiched between TFT substrate 100 and CF substrate200.

In TFT substrate 100, gate line 12 is formed on glass substrate 101, andinsulator 102 is formed so as to cover gate line 12. Data line 11 (FIGS.4 and 5) is formed on insulator 102, and insulator 103 is formed so asto cover data line 11. Common electrode 16 is formed on insulator 103,and insulator 104 is formed so as to cover common electrode 16. Pixelelectrode 15 is formed on insulator 104, and alignment film 105 isformed so as to cover pixel electrode 15. Although not illustrated, apolarizing plate and the like are formed in TFT substrate 100. Alaminate structure of each unit constituting pixel 14 is not limited tothe configurations in FIGS. 3 to 5, but any known configuration can beapplied.

Pixel electrode 15 and common electrode 16 are disposed opposite eachother with insulator 104 interposed between pixel electrode 15 andcommon electrode 16. As illustrated in FIG. 3, when viewed from thedisplay surface side, opening 16 a of common electrode 16 is disposed soas to overlap with the region (electrode portion) between two openings15 a adjacent to each other in the column direction of pixel electrode15. Similarly, when viewed from the display surface side, opening 15 aof pixel electrode 15 is disposed so as to overlap with the region(electrode portion) between two openings 16 a adjacent to each other inthe column direction of common electrode 16. A width in the columndirection of opening 16 a of common electrode 16 is substantially equalto a width (a width in the column direction of the electrode portion)between two openings 15 a adjacent to each other in the column directionof pixel electrode 15.

In CF substrate 200, black matrix 203 and colored portion 202 (forexample, a red portion, a green portion, and a blue portion) are formedon glass substrate 201, and overcoat layer 204 is formed so as to coverblack matrix 203 and colored portion 202. Alignment film 205 is formedon overcoat layer 204. Although not illustrated, a polarizing plate andthe like are formed in CF substrate 200.

Liquid crystal 301 is sealed in liquid crystal layer 300. Liquid crystal301 may be negative liquid crystal having a negative dielectricanisotropy or positive liquid crystal having a positive dielectricanisotropy.

Alignment films 105, 205 may be an alignment film subjected to a rubbingalignment treatment or an photo-alignment film subjected to aphoto-alignment treatment.

As described above, liquid crystal display device 1 has theconfiguration of the IPS (In Plane Switching) system. The configurationof liquid crystal display device 1 is not limited to the aboveconfiguration.

A method for driving liquid crystal display device 1 will briefly bedescribed. A scanning gate signal (gate-on voltage, gate-off voltage) issupplied from the gate line driving circuit to gate line 12. A videodata voltage is supplied from the data line driving circuit to data line11. When the gate-on voltage is supplied to gate line 12, thin filmtransistor 13 is turned on, and the data voltage supplied to data line11 is transmitted to pixel electrode 15 through drain electrode 22 andsource electrode 23. Common voltage (Vcom) is supplied from a commonelectrode driving circuit (not illustrated) to common electrode 16.Common electrode 16 overlaps with pixel electrode 15 with insulator 104interposed between common electrode 16 and pixel electrode 15, andopening 15 a (slit) is formed in pixel electrode 15. Therefore, liquidcrystal 301 is driven by an electric field from pixel electrode 15 tocommon electrode 16 through liquid crystal layer 300 and opening 15 a ofpixel electrode 15. Liquid crystal 301 is driven to controltransmittance of light transmitted through liquid crystal layer 300, andthus displaying the image. For performing color display, a desired datavoltage is supplied to data line connected to pixel electrode 15 ofpixel 14 corresponding to each of the red portion, green portion, andblue portion, which are formed by a vertical stripe color filter. Themethod for driving liquid crystal display device 1 is not limited to theabove method, but any known method may be adopted.

Liquid crystal display device 1 of the exemplary embodiment has acharacteristic electrode structure in FIG. 2, and thus achieving a wideviewing angle characteristic and high-speed response time. Configurationexamples of the electrode structures applicable to liquid crystaldisplay device 1 will be listed below. The description of the componentcommon to the configuration examples will be omitted as appropriate.

FIGS. 6A, 6B and 6C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 1. FIG. 6Aillustrates a planar configuration of one pixel electrode 15corresponding to one pixel 14, FIG. 6B illustrates a planarconfiguration of a portion of common electrode 16 corresponding to onepixel 14, and FIG. 6C illustrates a planar configuration of a state inwhich pixel electrode 15 and common electrode 16, which correspond toone pixel 14, overlap with each other. In FIG. 6C, for convenience,opening 16 a of common electrode 16 is indicated by a dotted line.

In configuration example 1 of FIG. 6, opening 15 a of pixel electrode 15is formed into a (horizontally-long) rectangular shape elongated in therow direction. The plurality of openings 15 a have a substantiallyidentical shape, and are arranged at substantially equal intervals inthe column direction. Openings 15 a are formed so as to be symmetricwith respect to center line c1 in the row direction of pixel 14. It isassumed that w1 is a width in the column direction of the region(electrode portion) between two openings 15 a adjacent to each other inthe column direction. Opening 16 a of common electrode 16 is formed intoa square shape in which one side has a length w2. The plurality ofopenings 16 a have a substantially identical shape, and are arranged atsubstantially equal intervals in the column direction. Openings 16 a areformed so as to be symmetric with respect to center line c1 in the rowdirection of pixel 14. Width w1 of opening 15 a is substantially equalto width w2 of opening 16 a (w1≈w2). As indicated by line c2 in FIG. 6,pixel electrode 15 and common electrode 16 are disposed such that acenter line of the width in the column direction of the electrodeportion of pixel electrode 15 is matched with a center line of the widthin the column direction of opening 16 a. That is, as illustrated in FIG.6C, each opening 16 a is disposed such that a whole opening regionoverlaps with the electrode portion of pixel electrode 15 in planarview.

FIGS. 7A, 7B and 7C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 2. Inconfiguration example 2, opening 16 a of common electrode 16 is formedinto a square shape, length w2 of one side is larger than width w1 ofthe electrode portion of pixel electrode 15 (w2>w1). Each opening 16 ais disposed so as to overlap with the electrode portion of pixelelectrode 15 in planar view. As indicated by line c2 in FIGS. 7A, 7B and7C, pixel electrode 15 and common electrode 16 are disposed such thatthe center line of the width in the column direction of the electrodeportion is matched with the center line of the width in the columndirection of opening 16 a. That is, as illustrated in FIG. 7C, eachopening 16 a is disposed such that an end (an upper side and a lowerside) in the column direction of opening 16 a protrudes evenly toopening 15 a in planar view.

FIGS. 8A, 8B and 8C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 3. Inconfiguration example 3, a position of opening 16 a of common electrode16 deviates to the column direction (in this case, to a lower side) froma position of opening 16 a of common electrode 16 illustrated inconfiguration example 2. That is, each opening 16 a is disposed suchthat center line c2 of the width in the column direction of theelectrode portion of pixel electrode 15 deviates from center line c3 ofthe width in the column direction of opening 16 a. As illustrated inFIG. 8C, the end (in this case, the lower side) in the column directionof opening 16 a protrudes to the region of opening 15 a in planar view.As illustrated in FIG. 8C, opening 16 a may be disposed such that theupper side of opening 16 a overlaps with the lower side of opening 15 a.Opening 16 a may be disposed such that the end (upper side) in thecolumn direction of opening 16 a protrudes to the region of opening 15 ain planar view.

FIGS. 9A, 9B and 9C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 4. Inconfiguration example 4, opening 16 a of common electrode 16 is formedinto a square shape, length w2 of one side is smaller than width w1 ofthe electrode portion of pixel electrode 15 (w2<w1). Each opening 16 ais disposed so as to overlap with the electrode portion of pixelelectrode 15 in planar view. As indicated by line c2 in FIGS. 9A, 9B and9C, pixel electrode 15 and common electrode 16 are disposed such thatthe center line of the width in the column direction of the electrodeportion of pixel electrode 15 is matched with the center line of thewidth in the column direction of opening 16 a. That is, as illustratedin FIG. 9C, opening 16 a is disposed such that an end (the upper sideand the lower side) in the column direction of opening 16 a falls withinthe region of the electrode portion of pixel electrode 15.

FIGS. 10A, 10B and 10C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 5. Inconfiguration example 5, the position of opening 16 a of commonelectrode 16 deviates to the column direction (in this case, to an upperside) from the position of opening 16 a of common electrode 16illustrated in configuration example 4. That is, each opening 16 a isdisposed such that center line c2 of the width in the column directionof the electrode portion of pixel electrode 15 deviates from center linec3 of the width in the column direction of opening 16 a. As illustratedin FIG. 10C, opening 16 a deviates so as to come close to the lower sideof opening 15 a in planar view. As illustrated in FIG. 10C, opening 16 amay be disposed such that the upper side of opening 16 a overlaps withthe lower side of opening 15 a. Opening 16 a may deviate so as to comeclose to the upper side of opening 15 a in planar view. The plurality ofopenings 16 a arranged in the column direction may deviate alternatelyto the upper side and lower side of opening 15 a in planar view.

FIGS. 11A, 11B and 11C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 6. Inconfiguration example 6, the plurality of openings 16 a of commonelectrode 16 are formed in the row direction. In FIGS. 11A, 11B and 11C,two openings 16 a are formed in the row direction. Alternatively, atleast three openings 16 a may be formed in the row direction. Openings16 a are formed so as to be symmetric with respect to center line c1 inthe row direction of pixel 14. The above configuration examples can beapplied as the size and disposition of opening 16 a.

FIGS. 12A, 12B and 12C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 7. Inconfiguration example 7, the plurality of openings 16 a arranged in therow direction deviate in the column direction. That is, pixel electrode15 and common electrode 16 are disposed such that center line c2 of thewidth in the column direction of the electrode portion of pixelelectrode 15, center line c3 of the width in the column direction ofopening 16 a in the left column, and center line c4 of the width in thecolumn direction of opening 16 a in the right column deviate from oneanother. In this case, center line c3 of the width in the columndirection of opening 16 a in the left column deviates upward from centerline c2 of the width in the column direction of the electrode portion ofpixel electrode 15, and center line c4 of the width in the columndirection of opening 16 a in the right column deviates downward fromcenter line c2 of the width in the column direction of the electrodeportion of pixel electrode 15. As illustrated in FIG. 12C, in planarview, opening 16 a in the left column deviates so as to come close tothe upper side of opening 15 a, and opening 16 a in the right columndeviates so as to come close to the lower side of opening 15 a.

FIGS. 13A, 13B and 13C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 8. Inconfiguration example 8, the plurality of openings 16 a arranged in thecolumn direction deviate alternately to the upper side and lower side ofopening 15 a in planar view.

FIGS. 14A, 14B and 14C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 9. Inconfiguration example 9, opening 16 a of common electrode 16 is formedinto a square shape, length w2 of one side is larger than width w1 ofopening 15 a of pixel electrode 15 (w2>w1). Center line c3 of the widthin the column direction of opening 16 a in the left column deviatesdownward from center line c2 of the width in the column direction of theelectrode portion of pixel electrode 15, and center line c4 of the widthin the column direction of opening 16 a in the right column deviatesupward from center line c2 of the width in the column direction of theelectrode portion of pixel electrode 15. As illustrated in FIG. 14C, inplanar view, opening 16 a in the left column deviates so as to comeclose to the lower side of opening 15 a, and opening 16 a in the rightcolumn deviates so as to come close to the upper side of opening 15 a.

FIGS. 15A, 15B and 15C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 10. Inconfiguration example 10, openings 16 a of common electrode 16 areconfigured with a plurality of groups having different sizes. In theexample of FIG. 15, openings 16 a are configured with a group ofopenings 16 a in the left column, a group of openings 16 a in the middlecolumn, and a group of openings 16 a in the right column. Opening 16 ain the left column and opening 16 a in the right column have anidentical shape, and opening 16 a in the middle column is smaller thanopening 16 a in the left column and opening 16 a in the right column.Opening 16 a in the middle column may be larger than opening 16 a in theleft column and opening 16 a in the right column. The aboveconfiguration examples can be applied as the disposition of opening 16a.

FIGS. 16A, 16B and 16C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 11. Inconfiguration example 11, openings 16 a of common electrode 16 areconfigured with a plurality of groups having different sizes. In theexample of FIG. 16B, opening 16 a having a small width and opening 16 ahaving a large width are alternately disposed in the column and rowdirections (into a matrix shape).

FIGS. 17A, 17B and 17C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 12. Inconfiguration example 12, openings 16 a of common electrode 16 aredisposed at equal intervals p1 in the column and row directions (thematrix shape).

FIGS. 18A, 18B and 18C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 13. Inconfiguration example 13, openings 16 a of common electrode 16 aredisposed such that the number of openings 16 a decreases toward thecenter of the pixel region in one pixel 14 (a distribution density islow), and such that the number of openings 16 a increases toward the end(the upper side and the lower side) of the pixel region (thedistribution density is high).

FIGS. 19A, 19B and 19C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 14. Inconfiguration example 14, openings 16 a of common electrode 16 aredisposed such that the number of openings 16 a increases toward thecenter of the pixel region in one pixel 14 (the distribution density ishigh), and such that the number of openings 16 a decreases toward theend (the upper side and the lower side) of the pixel region (thedistribution density is low).

In the above configuration examples 1 to 14 (FIGS. 6 to 19), opening 16a of common electrode 16 is formed into the square shape. Opening 16 aof common electrode 16 of the exemplary embodiment is not limited to thesquare shape, but various shapes can be applied.

For example, as illustrated in FIG. 20B (configuration example 15),opening 16 a may be formed into a (vertically-long) rectangular shapeelongated in the column direction. As illustrated in FIG. 21B(configuration example 16), opening 16 a may be formed into a triangularshape. Two side or three sides may have an identical length, or threesides may have different lengths. As illustrated in FIG. 22B(configuration example 17), opening 16 a may be formed into a rhombicshape. There is no particular limitation to an angle of the rhomboid. Asillustrated in FIG. 23B (configuration example 18), opening 16 a may beformed into a pentagonal shape. Opening 16 a is not limited to thepentagonal shape, but opening 16 a may be formed into a polygonal shapesuch as a hexagonal shape. As illustrated in FIG. 24B (configurationexample 19), opening 16 a may be formed into a circular shape. Opening16 a is not limited to the circular shape, but opening 16 a may beformed into an elliptical shape. Common electrode 16 may have aplurality of kinds of openings 16 a having different shapes.

In FIGS. 20A to 24C, the size and disposition of opening 16 a indicatethe size and disposition corresponding to configuration example 1 (FIG.6B). The size and disposition of opening 16 a in configuration examples15 to 19 are not limited to the configuration in FIGS. 20A to 24C, butthe configuration of configuration examples 2 to 14 (FIGS. 7A to 19C)can be applied to the size and disposition of opening 16 a inconfiguration examples 15 to 19.

In configuration examples 1 to 19 (FIGS. 6A to 24C), opening 16 a ofcommon electrode 16 is disposed so as to overlap with the electrodeportion of pixel electrode 15 in planar view. In the exemplaryembodiment, the disposition of opening 16 a of common electrode 16 isnot limited to configuration examples 1 to 19. For example, opening 16 aof common electrode 16 is disposed so as to fall within opening 15 a ofpixel electrode 15 in planar view. That is, the whole of opening regionof opening 16 a may be disposed so as to overlap with opening 15 a inplanar view.

FIGS. 25A, 25B and 25C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 20. Inconfiguration example 20, width w1 in the column direction of opening 15a is substantially equal to width w2 in the column direction of opening16 a (w1≈w2), and the center line of the width in the column directionof opening 15 a is matched with the center line of the width in thecolumn direction of opening 16 a. Opening 16 a is disposed so as to fallwithin opening 15 a in planar view.

FIGS. 26A, 26B and 26C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 21. Inconfiguration example 21, width w2 in the column direction of opening 16a is smaller than width w1 in the column direction of opening 15 a(w1>w2), and the center line of the width in the column direction ofopening 15 a is matched with the center line of the width in the columndirection of opening 16 a. Opening 16 a is disposed so as to fall withinopening 15 a in planar view.

FIGS. 27A, 27B and 27C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 22. Inconfiguration example 22, width w2 in the column direction of opening 16a is smaller than width w1 in the column direction of opening 15 a(w1>w2), and center line c2 of the width in the column direction ofopening 15 a deviates from center line c3 of the width in the columndirection of opening 16 a. Opening 16 a is disposed so as to deviateupward in opening 15 a in planar view. Opening 16 a may be disposed soas to deviate downward in opening 15 a in planar view.

FIGS. 28A, 28B and 28C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 23. Inconfiguration example 23, the plurality of openings 16 a arranged in thecolumn direction deviate alternately to the upper side and lower side ofopening 15 a in planar view.

FIGS. 29A, 29B and 29C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 24. Inconfiguration example 24, the plurality of openings 16 a of commonelectrode 16 are formed in the row direction. In FIG. 29B, two openings16 a are formed in the row direction. Alternatively, at least threeopenings 16 a may be formed in the row direction. Openings 16 a areformed so as to be symmetric with respect to center line c1 in the rowdirection of pixel 14. The configurations of configuration examples 20to 23 can be applied as the size and disposition of opening 16 a.

FIGS. 30A, 30B and 30C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 25. Inconfiguration example 25, openings 16 a of common electrode 16 areconfigured with the plurality of groups having different sizes. Openings16 a of each group are disposed so as to fall within opening 15 a inplanar view.

In the exemplary embodiment, the shape of opening 16 a of commonelectrode 16 is not limited to the above configuration examples. Forexample, opening 16 a may be formed into a rectangular shape extendingin the column direction so as to stride over the plurality of openings15 a of pixel electrode 15.

FIGS. 31A, 31B and 31C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 26. Inconfiguration example 26, openings 16 a are formed so as to be symmetricwith respect to center c1 in the row direction of pixel 14, and openings16 a extend in the column direction so as to stride over the pluralityof openings 15 a of pixel electrode 15. Opening 16 a is disposed so asto overlap with opening 15 a and the electrode portion of pixelelectrode 15 in planar view.

FIGS. 32A, 32B and 32C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 27. Inconfiguration example 27, the plurality (in FIG. 32B two) of openings 16a are arranged in the row direction, and formed so as to be symmetricwith respect to center c1 in the row direction of pixel 14.

FIGS. 33A, 33B and 33C are plan views schematically illustrating pixelelectrode 15 and common electrode 16 of configuration example 28. Inconfiguration example 28, two openings 16 a that extend in the columndirection so as to stride over the plurality of openings 15 a of pixelelectrode 15 and the plurality of square openings 16 a, which arearranged in the column direction and are smaller than the width of theelectrode portion of pixel electrode 15, are formed so as to besymmetric with respect to center c1 in the row direction of pixel 14.

In the above configuration examples 1 to 28 (FIGS. 6A to 33C), opening15 a of pixel electrode 15 is formed into the horizontally-longrectangular shape, the long sides of four sides constituting opening 15a extend in the row direction, and the short sides extend in the columndirection. In the exemplary embodiment, the shape of opening 15 a ofpixel electrode 15 is not limited to configuration examples 1 to 28. Forexample, as illustrated in FIG. 34A (configuration example 29), opening15 a of pixel electrode 15 is formed into the vertically-longrectangular shape, the long sides of four sides constituting opening 15a extend in the column direction, and the short sides extend in the rowdirection. In this case, for example, openings 16 a of common electrode16 are formed into a square shape, and arranged in the row and columndirections. Opening 16 a may be disposed so as to overlap with theelectrode portion of pixel electrode 15 (see FIG. 34C), or disposed soas to overlap with opening 15 a of pixel electrode 15. The configurationof each of the above configuration examples can be applied as the sizeand disposition of opening 16 a in configuration example 29. Asillustrated in FIGS. 35A to 35D, pixel electrode 15 may be formed into acomb teeth shape.

In the above configuration examples 1 to 29 (FIGS. 6A to 34C), pixelelectrode 15 is disposed above common electrode 16. However, liquidcrystal display device 1 of the exemplary embodiment is not limited toconfiguration examples 1 to 29. For example, as illustrated in FIG. 36,pixel electrode 15 may be disposed below common electrode 16. The shapeand disposition of opening 15 a in each of the above configurationexamples may be applied to common electrode 16, and the shape anddisposition of opening 16 a may be applied to pixel electrode 15. Thatis, opening 15 a of pixel electrode 15 and opening 16 a of commonelectrode 16 may be replaced with each other.

In liquid crystal display device 1 of the exemplary embodiment, asillustrated in FIG. 37, projection 206 that controls the alignment ofliquid crystal 301 may be formed on the side of liquid crystal layer 300of CF substrate 200. As illustrated in FIG. 38, projection 106 may beformed on the side of liquid crystal layer 300 of TFT substrate 100.Projections 106, 206 may be formed in both the substrates. There is nolimitation to the shape of projections 106, 206 and the number ofprojections per pixel.

According to the electrode structure of liquid crystal display device 1of the exemplary embodiment, initial alignment of liquid crystal becomesa direction substantially parallel or perpendicular to the sides ofopenings 15 a, 16 a. A plurality of domains having a small size areformed in each pixel. Therefore, the response speed of the liquidcrystal can be improved compared with the conventional lateral electricfield system liquid crystal display device. FIG. 39 is a graphillustrating simulations of the response characteristics in a lateralelectric field system liquid crystal display device of a comparativeexample and lateral electric field system liquid crystal display device1 of the exemplary embodiment. As can be seen from FIG. 39, according tothe configuration of liquid crystal display device 1 of the exemplaryembodiment, changes in rise and fall become steep, and the responsespeed becomes high. That is, the viewing angle characteristic and theresponse speed can be improved in lateral electric field system liquidcrystal display device of the exemplary embodiment.

The above configuration examples can be combined with each other asappropriate, and combined with a known configuration.

While there have been described what are at present considered to becertain embodiments of the application, it will be understood thatvarious modifications may be made thereto, and it is intended that theappended claims cover all such modifications as fall within the truespirit and scope of the invention.

What is claimed is:
 1. A liquid crystal display device, comprising: afirst substrate including a first display electrode and a second displayelectrode that is disposed opposite the first display electrode with aninsulator interposed between the first display electrode and the seconddisplay electrode; a second substrate disposed opposite the firstsubstrate; and a liquid crystal layer disposed between the firstsubstrate and the second substrate, wherein in each pixel, the firstdisplay electrode includes a plurality of first openings, the seconddisplay electrode includes a plurality of second openings disposedcorresponding to positions of the plurality of first openings, theplurality of first openings have a third opening and a fourth openingadjacent to the third opening, the third opening and the fourth openingare arranged in a first direction, the plurality of second openings havea fifth opening, the fifth opening is disposed between the third openingand the fourth opening in planar view, the fifth opening is disposedsuch that a center line of the width of the fifth opening in the firstdirection deviates from a center line of the width of an electrodeportion of the first display electrode between the third opening and thefourth opening in planar view, each of the plurality of first openingsis formed into a rectangular shape, and each of the plurality of secondopenings is formed into a square shape.
 2. The liquid crystal displaydevice according to claim 1, wherein the plurality of second openingshave a sixth opening, and the fifth opening and the sixth opening arearranged in the first direction.
 3. The liquid crystal display deviceaccording to claim 2, wherein the plurality of second openings have aseventh opening disposed between the third opening and the fourthopening, and the fifth opening and the seventh opening are arranged in asecond direction orthogonal to the first direction.
 4. The liquidcrystal display device according to claim 1, wherein a width of thefifth opening in the first direction is equal to a width of theelectrode portion of the first display electrode between the thirdopening and the fourth opening in the first direction or a width of thethird opening in the first direction.
 5. The liquid crystal displaydevice according to claim 1, wherein one of the first display electrodeand the second display electrode is disposed in a lower layer, andanother one of the first display electrode and the second displayelectrode is disposed in an upper layer with the insulator interposedbetween the first display electrode and the second display electrode. 6.The liquid crystal display device according to claim 1, wherein at leastone of the first substrate and the second substrate includes aprojection that controls alignment of liquid crystal.
 7. The liquidcrystal display device according to claim 1, wherein one of the firstdisplay electrode and the second display electrode is a pixel electrode,and another one of the first display electrode and the second displayelectrode is a common electrode.
 8. The liquid crystal display deviceaccording to claim 1, wherein the plurality of first openings aredisposed in parallel to each other, and the plurality of first openingsare disposed such that a long direction of the first opening is parallelto a short direction of the pixel.
 9. The liquid crystal display deviceaccording to claim 3, wherein the fifth opening and the seventh openingare disposed closer to the third opening than to the fourth opening. 10.The liquid crystal display device according to claim 3, wherein thefifth opening is disposed closer to the third opening than to the fourthopening, and the seventh opening is disposed closer to the fourthopening than to the third opening.
 11. A liquid crystal display device,comprising: a first substrate including a first display electrode and asecond display electrode that is disposed opposite the first displayelectrode with an insulator interposed between the first displayelectrode and the second display electrode; a second substrate disposedopposite the first substrate; and a liquid crystal layer disposedbetween the first substrate and the second substrate, wherein in eachpixel, the first display electrode includes a plurality of firstopenings, the second display electrode includes a plurality of secondopenings disposed corresponding to positions of the plurality of firstopenings, the plurality of first openings has a third opening and afourth opening adjacent to the third opening, the third opening and thefourth opening are arranged in a first direction, the plurality ofsecond openings has a fifth opening and a six opening adjacent to thefifth opening, both of the fifth opening and the sixth opening aredisposed between the third opening and the fourth opening in planarview, the fifth opening and the sixth opening are arranged in a seconddirection orthogonal to the first direction, the fifth opening isdisposed such that a center line of the width of the fifth opening inthe first direction deviates from a center line of the width of anelectrode portion of the first display electrode between the thirdopening and the fourth opening in planar view, the sixth opening isdisposed such that a center line of the width of the sixth opening inthe first direction deviates from a center line of the width of anelectrode portion of the first display electrode between the thirdopening and the fourth opening in planar view, the fifth opening isdisposed closer to the third opening than to the fourth opening, and thesixth opening is disposed closer to the fourth opening than to the thirdopening.